Manual de Plantas de Costa Rica 171 
found here at higher elevations than usual, e.g., Allophylus racemosus, Aphelandra 
scabra, Astronium graveolens, Bauhinia ungulata, Boerhavia coccinea, Calycophyl- 
lum candidissimum, Capparis indica, Casearia corymbosa, Chomelia spinosa, Croton 
hirtus, Cyrtopodium paniculatum, Dalbergia retusa, Diospyros salicifolia, Disocactus 
himantocladus, Erythroxylum havanense, Eugenia hiraeifolia, Forsteronia spicata, 
Guettarda macrosperma, Gyrocarpus jatrophifolius, Hyperbaena tonduzii, Inga vera, 
Jacquemontia pentantha, Lonchocarpus salvadorensis, Mentzelia aspera, Paullinia cu- 
ruru, Pisonia aculeata, Platymiscium parviflorum, Plumeria rubra, Psittacanthus rhyn- 
chanthus, Semialarium mexicanum, Thouinidium decandrum, and Turnera ulmifolia. 
Agave wercklei, endemic to this watershed, is known up to 2000 m, the highest eleva- 
tion for any Agave in southern Central America. All of the above underscores this val- 
ley as very important in terms of biogeographic and ecological studies, as well as the 
urgent need to conserve and protect its flora. 
General Valley and canyon of the Rio Grande de Térraba. This region extends, 
more or less, along the basin of the Rio General, which merges with the Rio Coto Brus 
in its lower reaches to form the Rio Grande de Térraba. Elevations range from ca. 300 
to 1000 m. It is characterized primarily by the tropical moist forest life zone (Tosi, 
1969), with a three- to four-month dry season (Herrera & Gomez P., 1993), and has a 
floristic composition unique in Costa Rica. Here we have found remnant populations 
of many species more typical of the Osa Peninsula, such as Annona amazonica, Barne- 
bydendron riedelii, Brosimum utile, Buchenavia tetraphylla, Calophyllum brasiliense, 
Caryocar costaricense, Chaunochiton kappleri, Clowesia warczewitzii, Copaifera 
camibar, Dalbergia frutescens, Gouania colombiana, Humiriastrum diguense, Ma- 
tayba apetala, Ocotea patula, O. pullifolia, Oenocarpus mapora, Pterocarpus viola- 
Rio Grande de Térraba (2000) 
